Saving saadc data into a micro SD card using fatfs example - FR_NOT_ENABLED

[Thiago]

Hello.

I am trying to write code to read data using saadc and write the sampled data in a micro SD card using fatfs.

I started from the fatfs example and initialized and configured the saadc exactly as in saadc example except that I changed the timer to sample 120 samples at every 1 ms.

 I configured a queue to received the sampled data. I store the data in the queue at every call to the saadc callback:

void saadc_callback(nrf_drv_saadc_evt_t const * p_event)
{
    if (p_event->type == NRF_DRV_SAADC_EVT_DONE)
    {
        ret_code_t err_code;

        err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, SAMPLES_IN_BUFFER);
        APP_ERROR_CHECK(err_code);  

        if(done < NUMBER_OF_PACKETS){
            err_code = byte_queue_write(p_event->data.done.p_buffer, SAMPLES_IN_BUFFER * 2);//If data cannot be written to queue                        
            done++;
        }
        else{
            NRF_LOG_INFO("DONE WRITING TO THE FILE");
        }
        
    }
}

In the while loop, if there is data in the queue, I try to get it and save it in the file on the SD card:

while (true)
    {
        //__WFE();      

        if(!(byte_queue_read(saadc_source, sizeof(saadc_source)))){
            unit16_2_uint8(saadc_source, saadc_destination);

            NRF_LOG_INFO("Writing to file " FILE_NAME "...");
            ff_result = f_open(&file, FILE_NAME2, FA_READ | FA_WRITE | FA_OPEN_APPEND);
            if (ff_result != FR_OK)
            {
                NRF_LOG_INFO("Unable to open or create file: " FILE_NAME ".");
                            
            }

            ff_result = f_write(&file, saadc_destination, sizeof(saadc_destination) - 1, (UINT *) &bytes_written);
            if (ff_result != FR_OK)
            {
                NRF_LOG_INFO("Write failed\r\n.");
            }
            else
            {
                NRF_LOG_INFO("%d bytes written.", bytes_written);
            }

            (void) f_close(&file);          

        }        
                            
    }

However, the f_open() function always returns FR_NOT_ENABLED

And the device ends up stuck here:

This error seems to happen in this location at the file ff.c:

However, If I call the function fatfs_example() I can save the example file NORDIC.TXT without any errors.

Would anyone happen to know what could be causing the error?

Thank you.

[ovrebekk]

Hi

Typically this happens if you forget to mount the drive before you try to access it. 

Do you make sure to call f_mount(..) anywhere?

Best regards
Torbjørn

[Thiago]

Hello!

Thank you for answering.

I call it as shown in the image:

I also added it in case f_open returns an error in the main while loop. But it returns FR_NOT_READY in the second call (also as shown on the image above).

FYI, it enters the main while loop with the status FR_OK, after the call of fatfs_init(). That is, everything seems fine until the program enters the while loop.